U.S. Pat. No. 4,252,802, issued Feb. 24, 1981 describes certain cephalosporin antibiotics having an acylamino substituent of the formula ##STR1## wherein R.sub.a and R.sub.b are independently hydrogen or methyl, R.sub.c is hydrogen, alkyl or alkylphenyl.
U.S. Pat. Nos. 4,337,197, issued Jun. 29, 1982, and 4,533,660, issued Aug. 6, 1985, describe O-sulfated .beta.-lactam hydroxamic acids having antibacterial activity. Preferred compounds, as disclosed in the patents, have the formula ##STR2## wherein R.sub.d is acyl, R.sub.e and R.sub.f are the same or different and each is hydrogen or alkyl, and M.sup.+ is hydrogen or a cation.
U.S. Pat. Nos. 4,638,061, issued Jan. 20, 1987, and 4,694,083, issued Sept. 15, 1987 describe pharmaceutically acceptable salts of [3S(Z)]-2-[[1-(2-amino-4-thiazolyl)-2-[[2,2-dimethyl-4-oxo-1-(sulfooxy)-3- azetidinyl]amino]-2-oxoethylidene]amino]oxy]acetic acid as antibacterial agents, which when compared to other O-sulfated .beta.-lactam hydroxamic acids have superior oral adsorption characteristics in a mammalian host, in conjunction with improved stability to .beta.-lactamase enzymes responsible for .beta.-lactam resistance in the clinic and also improved chemical stability.
U.S. Pat. No. 4,638,060, issued Jan. 20, 1987, describes O-sulfated .beta.-lactam hydroxamic acids having antibacterial activity and having the formula ##STR3## and pharmaceutically acceptable salt thereof, wherein R.sub.g is acyl, and n and m are each independently 1, 2 or 3 and X is a saturated carbon to carbon bond; n and m are each independently 1, 2, 3 or 4, the sum of n+m.ltoreq.5 and X is --O--, --S--, ##STR4## n and m are each independently 1, 2 or 3, the sum of n+m.ltoreq.4 and X is ##STR5## (wherein R.sub.h is alkyl, aryl, hydroxy, alkoxy, alkanoyloxy, carbamoyloxy, alkanoylamino, or ureido) or ##STR6## (wherein R.sub.i is hydrogen, alkyl, aryl, alkanoyl or carbamoyl); n and m are each independently 1 or 2, the sum of n+m.ltoreq.3 and X is ##STR7## (wherein R.sub.j is hydrogen, alkyl or aryl); or n and m are each 1 and X is --S--CH.sub.2 --S--, ##STR8## Preferred acyl groups are described as those of the formula ##STR9## wherein Y.sub.1 and Y.sub.2 are each independently hydrogen or methyl or Y.sub.1 and Y.sub.2 together with the carbon atom to which they are attached are cyclopropyl, cyclobutyl or cyclopentyl and Y.sub.3 is hydroxy, amino, or hydroxyamino.
U.S. Pat. No. 4,684,722, issued Aug. 4, 1987, describes O-sulfated .beta.-lactam hydroxamic acids having antibacterial activity and having the formula ##STR10## and pharmaceutically acceptable salts thereof, wherein R.sub.k and R.sub.m are the same or different and each is hydrogen or alkyl or R.sub.k and R.sub.m together are --(CH.sub.2).sub.n -- wherein n is 2,3,4 or 5, and R.sub.n and R.sub.o are the same or different and each is hydrogen or alkyl of 1 to 3 carbon atoms.